Around the world in a solar plane

Solar Impulse has already shown it can fly day, night without fuel

September 1, 2012

Barbara A. Schmitz

Bertrand Piccard and André Borschberg of Solar Impulse have already proven their one-seat airplane can travel day and night using no fuel. But now the pair is getting ready to show the world that is possible to travel around the world using only solar power in their next-generation prototype.

Their first prototype, HB-SIA, has a wingspan that is equal to that of an Airbus A340, but despite its size, it weighs only as much as an average car.

In 2010, the two flew the prototype—powered by 12,000 photovoltaic cells that cover its wings to absorb solar energy and transfer it to the aircraft’s four batteries—for 26 hours, proving that a solar-powered plane could also fly at night.

This July, however, the two proved that a solar airplane could fly from Europe to Africa and back using only solar power. The nearly 4,000-mile flight, completed two months after they took off, was finished in eight legs and covered four countries and two continents. The goal of this mission was to further prove the plane’s reliability, while providing a rehearsal for its round-the-world flight planned for 2015 in an updated version of the plane called the HB-SIB.

The around-the-world flight was originally scheduled for 2014, but in July, HB-SIB’s wing spar cracked and the final structural test failed.

“It’s the first time a final structural test has failed in the history of the project and even though it’s hard to accept it’s an extremely valuable learning experience,” the Solar Impulse website states. “Moreover, it has made room for some stimulating brainstorming sessions within the team not only on how to use the time gained to improve the reliability of the aircraft but also to further emphasize the project’s message and value.”

A tale of flying adventure, severe injuries, international political maneuvering, and an emergency at sea comes to life in "Floatplane Odyssey," a book that commemorates the twenty-fifth anniversary of Tom Casey’s 1990 around-the-world flight in a Cessna 206 on floats.